The number and types of electronic devices available to consumers have increased tremendously the past few years, and this increase shows no signs of abating. Devices such as portable computers; tablet, desktop, and all-in-one computers; cell, smart, and media phones; storage devices; portable media players; navigation systems; monitors; and others have become ubiquitous.
The complexity of these devices has similarly been increasing. Additional functionality, such as graphics processing, networking, increases in memory size, and others, has led to an increase in the number and types of circuits included in these devices. These circuits may be located on boards, such as main-logic boards, in these devices.
However, due to increases in complexity, it is becoming more difficult to include all these needed circuits on one board. Also, there is a desire to be able to customize devices to target user preferences and varying price points. These factors have led to an increase in the use of daughter or riser cards. These cards may include various circuits. A card may connect to main-logic board via contacts along an edge of the card, where the edge of the card may plug into a corresponding connector on the main-logic board. Use of these cards allows functionality to be moved off the main-logic board, and also allows different cards to be used in different device configurations.
Unfortunately, these connectors may consume space on the main-logic board. This increased space means the main-logic board can either support less functionality or has to grow correspondingly larger. The latter may also mean that the entire electronic device may have to increase in size.
Also, these connectors may degrade signal quality and high-speed performance. Specifically, a signal traveling from a circuit on a card to a circuit on a main-logic board may need to travel along a trace on the card to a contact at an edge of the card, then through a connector joining the card to the main-logic board. From there, the signal needs to travel along a trace on the main-logic board itself. These multiple connections may increase signal path resistance and reactance, as well as signal coupling, thereby degrading signal quality.
Cards supported by these connectors may also be of considerable size, weight, and complexity. A large mass may place high rotational, lateral, and other forces on the connector.
Thus, what is needed are connectors having a high density of contacts that may also provide improved performance at high-speeds and be robust enough for use with large, heavy cards.